Anhydrous metal chlorides and hydrogen chloride



Patented June 9, 1931 UNITED STATES JoHANNEs BRODE, AND CARL- wuas rnia,or; nnnwresiiarnN-oN-Trrmnrmm; ena- MANY, AssIGNoRs TO to.FARBENINDUSTRIE AKTIrNeE-sELLsoHAFT, 0F FORT-ON-THE-MAIN', GERMANY, AGoRPORA'rI NOFG BMaNY IANVHYDBOUS METAL GELOR-IDEs ir]; ymoemc mmn V INo Drawing. Application filed March 2a 1927, Serial no, irasssf in GamaMarch 23,1926} It is already known that anhydrous chlorides, such asaluminium chloride,can be produced by allowing a mixture ofcarbonmonoxid'and chlorine to act upon materials such as aluminium silicates,containing metallic oxide, in a glowing heat. Difliculties however areexperienced, according to this process, in heating the material and thereaction gases to the requisite temperatures, and maintaining them atthat temperature until the reaction is completed and, moreover, theemployment of pure carbon-monoxid is essential.

We have now found that gaseous mixtures, such as water gas, containingcarbon monoxid and a substantial amount, say 10 per cent by volume,,ormore, of hydrogen, may be employed with advantage if the same be treatedwitha suflicient amount of chlorine, preferably in exectly theequivalent quantity for both the carbon monoxid and the hydrogen, andthe resulting mixture, in which a reaction, accompanied by a substantialrise in temperature, occurs immediately after ignition be brought intocontact with the substances containing metallic oxids. At the resultingtemperature, the carbon monoxid and chlorine, or T the already 1 formedphosgene, react. very rapidly with the metallic oxid, anhydrous chlorideand carbon dioxid being formed;

No difliculty is experienced in'carryi'ng out this very highlyexothermic process in a perfectly continuous manner. Owing to the greatamount of heat"disengaged,-there is no need toprovide any specialinsulating means for the reactionchamber. As a rule, however, it isadvisable to employ furnaces which are linedwith refractory materialswhich resist the action of chlorine and are of low heat conductivity, sothat the outer shell remainsat a moderate temperature and may beconstructed of metal, such as iron.

In continuousworking, for example in a shaft furnace on rotary tubefurnace, ,the

material, such as kaolin, containing metallic oxid, is preferablybrought into contact wlth the gaseous mixture on the counterflow'princlple, the resldue, such as 's1l1ca, be1ngremoved elthercontinuously or at certam mtervals, by suitable means, near the gasintake. In the event of a non-volatile metallic chlori'd e,"- such aschromium; chloride, when chrome iron ore is used,"being formed duringthe reaction, thesame is removed withthe residues. iIn theproduction ofvolatile'chlo-.

FRANK- less completely" deposited in solid' 'or' liquid the state ofmist, this may easily be precipitated' by electrical means, for example,in a

be depo'sited'by electrical means.

Before being put to any furtherjuse,isuch" fdmn whenthegasesare cooled.Should the gas still contain portions of the"chloride,in 7

as' the preparation of hydrochloric acid, the hydrogen chloride ispreferably {separated completely from the metallic chlorides,"the1 last"traces of which, if necessary, may be;

dro'chloric acid. By this means, "pure hydrotrate the V nature of the-said invention but eliminated 'by washing with concentrated hy f L genchloride cangbe easily obtained,iin addi f v v A V the invention is notlimited to the example; A i

Example bricks. 950 cubic metr'es'of a gaseous mixturecomposed'of 26 percent of hydrogen,

21 per cent'of carbon monoxid, 47- per cent of chlorine, 3 per vcent ofcarbon dioxid an'd 3. per cent of nitrogen are then passed over ceedssmoothly without aid' of any external heating. The reaction gases arepassed gen chloride and carbon'dioxichand -proc 750 kilogrammes ofkaolin, in the condition of lumps, are dehydrated at a temperature" A ofabout 700? 0. man ironJfurnace, lined 1 with refractoryandchlorine-proof silicate through a series of water-cooled condensers anddeposit 560 kilogrammes of anhydrous aluminium chloride. If the gases,which still contain aluminium chloride vapor, are then passed through anelectrically operated deposition cell, a further 30 kilog rammes ofaluminium chloride will be thrown down. The residual gases are firstpassed through an, aqueous. solution of concentrated hydro chl'oricacid, andthen through absorption vessels charged with water, by whichmeans 2400 kilogrammes of hydrochloric acid, of approximately per centstrength, and free from aluminium, are recovere .c 1

The production ofthe aluminium chloride may be rendered continuousbyrremo-ving, in a regular manner, the silica, formed,

from the kaolin, and introducingjcorrespond ing fresh quantities. ofdehydrated kaolin. It'is' preferable that the siliceous. residues,

should be removed whilethey still containabout 2, to 3, per cent of A1 0because, in

thisv condition, they retain their lumpy character and pass freelythrough the furnace.

' 'llhe chlorination of chrome iron ore can:

beieffectedin. a'similar manner, in which case ferric chloride is theprincipal Volatile-chloride formed, whilst the chromium chloride alsoproduced. is withdrawn with the residue.

.7 'Weclaim i I, Theprocess; of producing. anhydrous metal chlorides andhydrogen chloride, which comprises acting on material comprising metaloxide with a gas-mixture containing carbon monoxide, at least 10 percentby volume of hydrogen, and chlorine at av'high temperature. i I

2. The process of producing anhydrous; aluminiumchloride and hydrogenchloride,

which comprises acting on material comprising aluminium oxide with a gasmixture con; taming carbon. monoxide, at least. 10 percent y hightemperature.

ntestimony whereot we have hereunto set ourhands, v v v J OHANNES BRODE.1

I CARL WURSTER- Volume of hydrogen, and chlorine at, a,

